"""一组可用于表示电动汽车的类"""

from car import Car

class Battery():
    """一次模拟电动汽车电瓶的简单尝试"""

    def __init__(self, battery_size = 70):
        """初始化电瓶的属性"""
        self.battery_size = battery_size

    def describe_battery(self):
        """打印一条描述电瓶容量的消息"""
        print("This car has a " + str(self.battery_size) + "-kwh battery")

    def get_range(self):
        """打印一条消息，指出电瓶的续航里程"""
        if self.battery_size == 70:
            range = 240
        elif self.battery_size == 85:
            range = 270

        msg = "This car can go approximately " + str(range)
        msg += " miles on a full charge."
        print(msg)

    def upgrade_battery(self):
        if self.battery_size != 85:
            self.battery_size = 85


class ElectricCar(Car):
    """
    电动汽车的独特之处
    初始化父类的属性，再初始化电动汽车特有的属性
    """

    def __init__(self, make, model, year):
        """初始化父类的属性，再初始化电动汽车特有的属性"""
        super().__init__(make, model, year)
        self.battery = Battery()  # 将一个Battery实例用作ElectricCar类的一个属性